A simplified 3GPP network combining legacy 2G and 3G networks with a LTE (long term evolution) architecture is illustrated in FIG. 1. In LTE, the radio resources for the bearers are controlled by the RBS (radio base station) node (eNodeB). In 2G/3G networks, the radio resources for the bearers are controlled in the RNC (radio network controller) nodes.
The QoS (quality of service), policy and charging control in EPC (evolved packet core) networks is typically performed by the PCRF (policy and charging resource function) entity. In principle, other nodes such as PGW (packet data network gateway or PDN gateway) can also perform basic policy control actions. In a LTE network, initiated QoS is supported where the operator service network initiates the setup of a new bearer. The setup is initiated with a PDP (packet data protocol) context towards the PCRF that specifies the flow descriptors, the application and the QoS requirement. The PCRF then makes the policy decision and downloads the rule for the new bearers to the PGW which initiates the new bearer setup procedure.
According to this procedure, a new bearer is set up or the existing bearer is modified for each subscriber upon a new content request (regardless of whether the PCRF is involved). However, such types of point-to-point delivery service do not scale well. The resources needed to distribute the content increase proportionally with the number of subscribers and the size of the transferred content. This is particularly inefficient for on-line streaming services and ‘push’ services such as, for example, SMS (short message service), WAP-push (Wireless Application Protocol), podcast etc., where many subscribers request the same content.
It is possible to simultaneously deliver multimedia content to a number of users in a specific location (ranging from one cell up to the entire network) through the use of MBMS (multicast-broadcast multimedia service) push service, which is a broadcast service tailored for mobile networks. While MBMS solves the scalability problem of content delivery, it is still suboptimal for a number of different reasons listed below:
(i) The timing of content delivery is critical. On one hand, the content broadcast should take place when most of the subscribers to the content are reachable (i.e. accessible). That is, it is dangerous to use the would-be most optimal period of night hours for content download. On the other hand, for some content types (e.g., news) the time gap between the content creation and delivery time may be very short;
(ii) During the content delivery, certain subscribers to push services are out-of the radio range (i.e. “unreachable” or not accessible) or have bad radio conditions which would trigger a large number of subsequent point-to-point file-repair procedures which degrades the network efficiency and jeopardizes the delivery of the content in due time; and
(iii) Upon the start of (streamed media) content delivery by MBMS systems, there could be many subscribers with bad radio coverage. That is, the QoS bearers for the media delivery cannot be setup for a large fraction of subscribers resulting in a bad grade of service (GoS).
In order to, at least partially, overcome these issues, a mechanism that is aware of the subscribers' environmental conditions during content delivery is needed. An architecture that can facilitate such functionality has been proposed by A. Vetro, et al., in U.S. Pat. No. 7,013,149 B2. It is based on a central entity called an application service provider (ASP). The ASP of Vetro controls the delivery of multimedia services based on environmental information such as location parameters, network conditions, delivery capabilities, time parameters and subscriber mobility characteristics. The architecture of Vetro is illustrated in FIG. 2.
As described in Vetro (referring to FIG. 2), mobile terminal devices 205 (e.g., cellular phones and portable computing devices) are connected to a service manager 210 and an application service provider (ASP) 220 via an access network 230. The access network 230 can include wired and wireless portions and there can be multiple ASPs (e.g., local businesses, government agencies, etc.) in a particular locale. The characteristics of different networks are expressed in terms of capacity, available bandwidth, error characteristics and latency. Each mobile device is characterized by different capabilities, such as the multimedia formats that the device can receive, as well as processing and display constraints.
The location of a particular mobile device is determined by a geolocation component 240 which can be part of the network 230. An environment description 250 generated by the ASP 220 includes the location of the mobile device, the characteristics of the device and network, and other factors of the usage environment. A description parser 260 parses the environment description 250 with a schema or grammar 270. This provides a consistent interface which can be processed in a predictable manner. The parsed environment description is available to the service manager 210. The service manager 210 maintains a database 280. The service manager or ASP 220 allows authenticated devices to access multimedia services stored in the database 280.
Vetro, however, also has some drawbacks such as: (1) The efficiency issues regarding the service delivery still exist due to the personalized nature of the service; (2) The architecture of Vetro requires dynamic per-subscriber statistics signalling and storage which raises scalability issues in a real network with a high number of subscribers and content; (3) The content transfer generally takes place between the application service provider and the mobile device when conditions for content delivery are fulfilled by the current environment description. If a good match cannot be found, then the content manager attempts to satisfy the content transfer by itself. In order to accomplish this, the content is pre-stored in the database. Since both the database and the service provider's server are centrally placed, all content delivery will load the access backhaul. It is not possible with this method to offload the mobile access backhaul; and (4) Since the control is located in the core network, it is also not possible to get instantaneous feedback of the available radio resources in order to achieve a spectrum-efficient content scheduling.
What is desired, therefore, is a method and apparatus for overcoming the limitations described above.